Snap acting switch



Aug'. 1, 1961 A. F. RAAB 2,994,750

SNAP ACTING SWITCH Filed Hay 2, 1958 United States Patent C 2,994,750SNAP ACTING SWITCH Andrew F. Raab, Morton Grove, Ill., assignor toLittelfuse, Inc., Des Plaines, Iii., a corporation of Illinois Filed May2, 1953, Ser. No. 732,571 2 Claims. (Cl. 20G- 67) The principal objectof this invention is to provide irnprovements in a snap acting switchhaving a pivotally mounted carrier which is snapped in oppositedirections about its pivot axes, the improvements being directed to themanner of stopping the carrier in its snapping movement and to themanner of supporting the contact member on the carrier for movementthereby.

Such a snap acting switch may be of the type including a pivotallymounted carrier having a pair of angularly spaced seats and a guideelement therebetween and a double faced lock cam. A trip lever isadapted alternately to engage the spaced seats of the carrier forpivotally moving the carrier in opposite directions. A lock bar isslidably mounted adjacent the carrier and has a lock lug thereonnormally alternately engaging the faces of the lock cam to preventpivotal movement of the carrier in said opposite directions. Means areprovided for resiliently pressing the trip lever against the seats ofthe carrier and for slidably moving the lock bar to disengage the locklug thereof from the lock cam of the carrier to snap the carrier inopposite directions about its pivot axis.

In the past, the snapping of the carrier in its opposite directions hasbeen stopped at its alternate positions by the lock lug on the lock barand, as a result, the lock lug has often broken away because of fatiguethereof because of the incessant pounding thereof by the snappingcarrier. To eliminate this difiiculty, Ellithorpe Patent No. 2,604,-793, dated July 29, 1952, proposed the use of fixed stops on the housingto stop the snapping movement of the carrier but this introduced certainother objectionable factors. In accordance with one aspect of thepresent invention, the pivotally mounted carrier is provided with a pairof angularly spaced stop shoulders which engage the sturdy slidablymounted lock bar when the carrier is snapped to one position or theother for stopping the carrier at said positions. `Fatiguing andbreakage of the stop lug and the objectionable factors of the saidEllithorpe patent structure are thus eliminated.

In regard to the other aspect of the present invention, the contactmember, which selectively engages the spaced stationary contacts, iscarried by a bowed leaf spring which affords contact pressure betweenthe contact member and the contacts. The bowed leaf spring is providedwith a pair of holes which receive a pair of spaced projections on thecarrier for readily and resiliently mounting the contact member on thecarrier to move the contact member into selective engagement with thecontacts as the carrier is snapped in opposite directions about itspivot axis.

Further objects of this invention reside in the details of constructionof the snap action switch and in the cooperative relationships betweenthe component parts thereof.

Other objects and advantages of this invention will become apparent tothose skilled in the art upon reference to the accompanyingspecification, claims and drawing in which:

FIG. 1 is a perspective view of the snap action switch of thisinvention.

FIG. 2 is a vertical sectional view taken substantially along the line2-2 of FIG. l and illustrating the snap acting switch in releasedposition.

FIG. 3 is a vertical sectional view taken substantially along the line3-3 of FIG. 2.

FIG. 4 is a vertical sectional View similar to FIG. 2

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but illustrating the snap acting switch as it is being operated.

FIG. 5 is a partial vertical sectional view similar to FIGS. 2. and 4but illustrating complete operation of the snap acting switch.

FIG. 6 is a horizontal sectional view taken substantially along the line6-6 o-f FIG. 2.

FIG. 7 is a perspective view of the lock bar.

FIG. 8 is a perspective view of the tripping lever.

FIG. 9 is an elevational view of the pivotally mounted carrier butshowing the side thereof opposite to the side illustrated in FIGS. 2, 4and 5.

FIG. 10 is an exploded perspective view illustrating the manner ofsecuring the contact member to the carrier.

The snap action switch of this invention is generally designated at 10and it may be utilized as a Vfoot operated switch for dimming theheadlights of an automotive vehicle. It includes a housing 11 which ispreferably diecast from suitable metal. The housing 11 has an upperportion 12 having a cylindrical cavity which opens upwardly and a lowerportion 13 having a cavity which opens laterally as indicated at 15. Thehousing has a transverse partition 14 between the upper and lowercavities. The lower portion of the housing is provided with suitableapertured mounting ears 16 for mounting the snap action switch.

The lower portion 13 of the housing has a bearing member 18 projectinginto the cavity and this bearing member 18 is provided with a hole 19-for receiving a pin projection 20 on a carrier 21. The carrier 21 ispreferably made from an electrical insulating material such as nylon orthe like. The pin projection 21 pivotally mounts the carrier in thebearing member 1S of the housing. The top edge of the carrier 21 isprovided with a pair of angularly spaced seats 22 and 23 and with apointed guide element 24 therebetween. The rear `face of the carrier 21adjacent the bottom thereof, as shown in FIG. 9, is provided with adouble faced lock cam 25 which is formed by recessing the rear face ofthe carrier as indicated at 26 and 27.

A lock bar 30 formed of stamped steel or the like is slidably mounted inan opening 31 in the transverse partition 14 of the housing and it isalso provided with an elongated slot 32 which encompasses the pinprojection 20 of the carrier 21. The lock bar 30 is thus guided forupward and downward longitudinal movement. The lock bar 30 extendsadjacent the rear face of the carrier 21 and is provided with a lock lug33 which extends into the recess 26 and 27 of the carrier and engagesthe opposite sides of the lock cam 25 depending upon the position of thecarrier. The upper end of the lock bar 30 is provided with an extension34 for securing a button or cap 35 to the lock bar, this being done bypeening the extension 34. A coil spring 36 is arranged between the cap35 and the transverse partition 14 for resiliently maintaining the capand the lock bar 30 in an elevated position with the lock lug 33 at theupper ends of the grooves 26 or 27.

The lock bar 30 is provided with an elongated slot 38 which receives thetransverse arm 39 of a trip lever 49, the arm 39 having a notch 41 formaintaining the trip lever in place in the slot 38 in the lock bar 30.The trip lever 40 extends downwardly -adjacent the lock bar 36 andthrough the opening 31 in the transverse partition 14 to a pointadjacent the spaced seats 22 and 23 and guide element 24 on the carrier21. Here, also the lock bar 40 may be formed from stamped metal. Acupped spring seat 43 is slidably mounted on the lock bar 30 above thearm 39 of the tripping lever 40. A spring 44 is interposed between thespring seat 43 and the cap 35 for resiliently pressing the spring seat43 against the arm 39 of the tripping -lever 40. This operates normallyto maintain the tripping lever at the lower end of the slot 38 and in aposition substantially radial to the pivot axis on the carrier 21 asillustrated in FIG. 2.

FIG. 2 illustrates the parts in their normal released positions with thecarrier maintained in one position by reason of the lock lug 33 engagingone side of the lock cam 25. When the cap 35 is depressed, asillustrated in FIG. 4, the lower end *42 of the tripping lever 40 isguided by the guide element 24 into the seat 22, the tilting of the triplever 40 being permitted by reason of its association with the slot 38and the spring seat 43. As depression of the cap 35 continues, the lockbar 30 is moved downwardly while downward movement of the trip lever 40is prevented by the locked carrier 21. As a result, the yforce of thespring 44 increases. When the lock bar 30 is depressed suiiiciently torelease the lock lug 33 from the lock cam 25, the spring 44 operatesthrough the trip lever 40 to snap the carrier 21 to the oppositeposition as shown in FIG. 5. When the cap 35 is released, the lock bar30 and the trip lever 40 are raised by the spring 36 to the positionillustrated in FIG. 2 and at this time the carrier 21 is locked in theopposite position, as -illustrated in FIG. 5, by the lock lug 33engaging the other side of the Alock cam 25. The carrier 21 may then besnapped from the position shown in FIG. to the position shown in FIG. 2.by the same operation as described above and, accordingly, a furtherdescription is not considered necessary. In this way, the pivotallymounted carrier is selectively snapped in opposite directions about itspivot axis.

The rear face ofthe carrier 21 is provided with a pair of angularlyspaced stop shoulders 46 and 47 which are adapted automatically toengage opposite sides of the lock bar 30 when the carrier is snappedfrom one position to the other. This is illustrated in FIG. 5 where thecarrier has snapped 4from the position shown in FIG. 2 to the positionshown in FIG. 5. Thus, stopping o-f the carrier in its snapping movementfrom one position to the other is accomplished by the stop shoulders 46and 47 engaging the rugged and strong lock bar 30. This preventsfatiguing of the relatively weak stop lug 33 and accurate positioning ofthe carrier 21 with respect to the lock bar 30 is assured.

The front face of the carrier 21, as illustrated more clearly in FIG.l0, lis provided witha pairof spaced projections 50 having shoulders 51.A contact member 52 is suitably secured, as by spot welding 53, to abowed leaf spring 5'4. The bowed leaf spring 54 has a pair of holes 55therein which receive the spaced projections 50 on the carrier, thebowed leaf spring seating against the shoulders 51. The initial bowingof the leaf spring 54 is such that'the holes 55 engage the sides of theprojections 50 so as to secure the leat spring and hence, the contactmember to the carrier.

A terminal member 57, yformed of suitable insulating material such asBakelite or the like, is secured in the opening in the lower portion 13of the housing 11 as by means of offsetting the housing thereat asindicated at 58 in FIG. 1. Secured within holes in the terminal member57 are contacts 59,V 60 and 61, the inner ends of these contacts beingturned over, as illustrated in FIG. 3 so as to be engaged by the contactmember 52. The outer ends of the contacts 59, `60 and 61 are providedwith suitable holes for facilitating electrical connection thereto. Thecontact 59 is in substantial alignment with the pivot axis of thecarrier 21 while the terminals 60 and 61 are spaced apart and spaced yaconsiderable distance from the pivot axis. The contact member 52continually engages the contact 59 and alternately engages the contacts60 and 61 as the carrier 21 is snapped from one position to the other.rIlhe bowed leaf spring 54, in addition to securing the contact member52 to the carrier 21 also affords desired contact pressure between thecontact member 52 and the contacts 59, 6 0 and 61. Accordingly,extremely satisfactory switching operations are obtained and, inaddition to providing a wiping action at contacts 60 and `61, a wipingaction is also provided at contact 59.

While yfor purposes of illustration, one form of this invention has beendisclosed, other forms thereof may become apparent to those skilled inthe art upon reference to this disclosure and, therefore, this inventionis to be limited only by the scope of the appended claims.

I claim as my invention:

l. In a snap acting switch including a pivotally mounted carrier havinga pair of angularly spaced seats and a guide element therebetween and adouble faced lock cam, a trip lever adapted alternately to engage thespaced seats of the carrier yfor pivotally moving the carrier inopposite directions, a lock bar slidably mounted adjacent the carrierand having a lock lug thereon normally alternately `engaging the facesof the `lock cam to prevent pivotal movement of the carrier in saidopposite directions, and means for resiliently pressing the trip leveragainst the seats of the carrier and for slidably moving the lock bar todisengage the lock lug thereof from the lock cam of the carrier to snapthe carrier in opposite directions -about its pivot axis, a pair ofangularly spaced stop shoulders on the carrier engaging the lock barwhen the carrier is snapped to one position or the other for stoppingthe carrier at said positions, a pair of spaced projections on thecarrier, a bowed leaf spring having its concave side facing the carrierand having holes therein receiving and resiliently engaging the spacedprojections by which t'he bowed -leaf spring is removably mounted on thecarrier, a contact member secured centrally to the bowed leaf spring,and spaced contacts facing the convex side of the bowed leaf spring andselectively engaged by the contact member as the carrier is snapped inopposite directions -about its pivot laxis, said bowed leaf springaffording contact pressure between the contact member and the contacts.

2. In a snap acting switch including a pivotally mounted carrier havinga pair of angularly spaced seats and a guide element therebetween and adouble faced lock cam, a trip lever adapted alternately to engage thespaced seats of the carrier for pivotally moving the carrier in oppositedirections, a lock bar slidably mounted adjacent the carrier and havinga lock lug thereon normally alternately engaging the faces of the lockcam to prevent pivotal movement of the carrier in said oppositedirections, and means for resiliently pressing the trip lever againstthe seats of the carrier and vfor slidably moving the lock bar todisengage the lock lug thereof from the lock cam of the carrier to snapthe carrier in opposite directions about its pivot axis, a pair ofangularly spaced stop shoulders on the carrier engaging the lock barwhen the carrier is snapped to one position or the other for stoppingthe carrier at said positions, spaced contacts, a contact member adaptedto selectively engage the spaced contacts, a bowed leaf spring carryingthe contact member at the center of the convex side thereof and`affording contact pressure between the contact member and contacts andhaving a pair of spaced holes therein, and a pair of spaced projectionson the carrier received in and engaging the edges of the holes in thebowed leaf spring for resiliently removably supporting the latter andfor moving the contact member to selectively engage the contacts as thecarrier is snapped in opposite directions about its pivot axis.

References Cited in the le of this patent UNITED STATES PATENTS2,085,539 Morris June 29, 1937 2,647,180 Tregoning July 28, 1953 FOREIGNPATENTS 1,111,214 'France oct. 2.6, 1955

